"index.php*" match in dashboard privileges overlays a bit
with "index.php?logout" so that we'll have to hardcode an
exception for now.  Other approaches to be taken here mid-
term are 'visibility="always"' in Menu.xml or restructure
the logout link under /ui/logout or /logout.php.

PR: https://forum.opnsense.org/index.php?topic=3431.0